One type of network comprising a plurality of packet transmitting and receiving nodes is a telecommunicating signaling network interconnecting telecommunication exchanges, known as the Signaling System 7 (SS7) as defined by the International Telegraph and Telephone Consultative Committee (CCITT) or the American National Standard Institute (ANSI) standards body. In such a system, information relating to the connection of telephone calls is communicated between exchanges via the SS7 network in a packet format. From time to time it is necessary to replace an exchange which is technologically obsolescent with an exchange that embodies the state of the art in telecommunications switching products to offer more features, carry more traffic, and support state of the art telecommunications services. Typically this is done by replacing the entire switching system of the exchange together with its interface connections to subscriber lines and trunk circuits connecting the exchange to the remainder of the telecommunications network. Such replacement must be done without significantly interrupting telephone service normally provided by the exchange. This is a well known problem in the art. In prior art systems using in-band signalling, wherein the signaling information related to telephone calls is transmitted over the same interexchange trunks as the calls themselves, the problem is solved by performing a flash cut transfer of all lines and trunks, from the existing exchange to the new exchange. One problem associated with this approach is that the new exchange is expected to handle all telephone traffic immediately after the flash cut. A flash cut may have to be made back to the old system if substantial errors are present in the new system. Catastrophic failures are more likely to occur when live telecommunications traffic is transferred from one system to another. With the SS7 out of band signaling arrangement, the procedure is even more complex since such a flash cut also requires the simultaneous interchange of connections of the old and the new exchanges in the signaling network. Signaling messages are transferred between exchanges on the basis of assigned addresses. One prior art approach to the aforementioned problem is to establish the new exchange as a separate node with its own unique node address identification, connecting a new set of telecommunication transmission trunks from the new switching system to the remainder of the network, performing tests on the trunks prior to cutover, and doing a flash cut of the signaling links simultaneously with the cutover of the trunks. That approach, however, requires that all of the exchanges which communicate with the exchange change their packet addressing from the address of the old exchange to that of the new, at the instant of the flash cut.
These prior art approaches to the replacement of a node, or the inner workings of a node, in a multi-node system operating in real time which relies on packetized messages for operational control, have serious drawbacks. A standard flash cut procedure without precut over testing of connections is subject to high failure rates. The prior art approach of installing all new interconnecting trunks is expensive and the assignment of a separate packet address requires cumbersome changes in all other nodes of the packet network.